I'm not sure how it works in Australia, but my doctor explained all the risks and benefits during my surgery consultation. He was patient and answered all my questions (not all doctors are that way, some you have to push a bit). I signed a paper before I went in for surgery that basically said that the doctor explained everything and that I understood the risks of surgery as well as those of the anesthesia.
Anesthesia does have risks, but it is also very safe. Most people have no complications. I know it's weird (or even scary) to think about yourself being unconscious that way, but trust me, you don't even know it at the time. They give you the IV, they tell you to count backwards from 100 and by the time you get to 95, that's it. You're totally asleep. You're groggy when you wake up. They may ask you if you want a Popsicle (the breathing tube they had down your throat makes it sore).
I would look online at some other medical websites and see what they actually do when you have your eardrum repaired. You'll also see the risks and benefits on there. Then you can make a list of questions to ask the doctor. The more you know, the more you'll feel in control.